When non-metals combine Molecular Compounds When non-metals combine

Non-Metal Elements Appear on the right side of the periodic table (except for Hydrogen) Need to take electrons Examples: Halogens (F, Cl, Br)

When they get together things don’t work out as well as when metals meet non-metals because they both want electrons Let’s say that two Fluorine atoms bump into each other

Neither one is happy. They both need an electron What can they do when they both need an electron

Finally, they figure something out And they make a deal They agree to each share one of their electrons

Now they’re both happy When two atoms share electrons it is called a covalent bond. And they form something called a molecule. This molecule has the formula F2

Here’s another example: Carbon and oxygen Let’s not worry about naming them right now. That can be a little complicated so we’ll save it for grade 10 Here’s another example: Carbon and oxygen Oxygen needs two electrons Carbon needs four

So oxygen gets a friend Each one shares two electrons with the carbon atom And the carbon atom shares two electrons with each oxygen

And they look something like this And everyone’s happy! And the formula is CO2

When you show what the model looks like it is called a structural formula When you make one, you draw a line to show two atoms sharing an electron So F2 looks like this F-F And CO2 looks like this O=C=O

Practice Give the formula for a molecule when each of the following elements combine Hydrogen and Oxygen Iodine and Iodine Hydrogen and Chlorine Hydrogen and Nitrogen Nitrogen and Oxygen Oxygen and Oxygen

More Practice! Now make the structural formula for each one Hydrogen and Oxygen Iodine and Iodine Hydrogen and Chlorine Hydrogen and Nitrogen Nitrogen and Oxygen Oxygen and Oxygen